He's The Only Guy Working There

Side 1 says... My boyfriend and I met at work almost a year ago. We worked at Pier 1, and he still works there. He is the only guy working there, and he has a history of hooking up with the girls there (before me, of course). One girl that he worked with and ended up sleeping with is coming back to work there. And there's already one working there that he has a history with. Now he's never cheated on me, and I don't think he would, but it really bugs me that the girls he works with all flirt with him and call him outside of work. And I should mention that he used to model, so he's not to bad to look at. As much as i try not to get mad at him, it slips every once in a while. How should I handle this?